Density of a given metal

Free essay example:

Density practical Report

Name: Casey Going

Date: 16/10/08

Focus question: Can an unknown metal be determined by its mass, volume and density

Hypothesis: it is hypothesised that the heavier metals with greater density and volume will be more likely to be metals like lead and the metals with small mass, density and volume are more likely to be metals such as tin and aluminium.

Variables identified

Type of variable

Treatment

Metal type

Independent variable

Cu, PB, Fe, Al, Zn, Sn

Volume of metal and mass of metal

Dependent Variable

Volume of metal was determined by displacement of water. The mass will also be determined. Density will be calculated

temperature

Controlled Variable

All metals will be kept at 25 degrees centigrade

Physical shape of metal

Controlled Variable

All metals folded out straight to keep air bubbles from distorting the displacement.

N.B original volume of water was considered but was decided that it would not have any affect on volume.

Experimental Report

The metals all sat in the water and did not float. None off them reacted with the water and gave off bubbles. The heavier metals also felt heavier in the hand were also larger in physical size. The lighter metals were smaller in physical and mass size.

Unknown Metal Mass and Volume

metal

mass + 0.1 (g)

initial volume of water +0.5 (cm3)

Final volume of water + 0.5 (cm3)

1

26.80

50.00

53.00

2

28.50

50.00

52.50

3

22.00

50.00

52.50

4

21.00

50.00

52.00

5

6.30

50.00

50.80

6

2.60

50.00

51.00

7

11.00

50.00

51.10

average

16.89

50.00

51.84

Processed data

The data obtained from this experiment has been manipulated in this way to show the density. The data has been put through the formula density=mass/volume. This will determine the density which then can be graphed.

The calculation made from the raw data was that initial volume was taken away from final volume. This first then gave volume of the metals which then could be out into the formula density=mass/volume. Therefore density=26.8/3. This gave the density which then could be graphed. The r2 in the graph is the density. The error for the density was calculated by finding the percentage error of volume and mass and then adding them together. This created quite a large error as the percentage error was as big as the reading is some cases.

Presentation

Unknown Metal Mass, Volume and Density

This graph had such large areas due to equipment being very inaccurate. The data collected had errors almost as large as the reading itself thus making the percentage error very large.

The metals had a large range of density’s which was partly due to inaccurate equipment making very large errors.

This graph directly above shows the percentage error against the reading. As can be seen the percentage error is very large due to when measuring the volume the error + 0.5 was as large as the volume of the metal itself.

Conclusion and Evaluation

These density somewhat support the hypothesis that the heavier metals are lead and the lighter ones aluminium. The readings taken were too inaccurate to justify each metal. Each density at least had an error of + 15% but in some cases reached + >50%. This was due to highly inaccurate measuring equipment especially the measuring cylinder. It is to hard to tell which metal is which with the readings taken and calculated due to the large errors in them.

Limitations of experimental design

The experimental design definitely did not help answer the question as there were to many errors to determine which metal was which. There were a few limitations to the design of this experiment. They were:-

Inaccuracy of equipment (especially the measuring cylinder)

Metals be unnamed (a,b,c, etc) so that they could have been mixed up

The main and foremost error in this experiment was definitely the equipment as it was so inaccurate that it gave errors as large as the reading itself. Both of these systematic errors made it harder to provide proper data to be manipulated into the right density for each metal.

Suggestions for Improvement

To improve this experiment it is suggested that higher accuracy equipment is provided as this will give smaller errors and so the overall percentage error

So in conclusion, my hypothesis that the higher the density the greater the volume of a drop of that liquid was correct Evaluation Errors Effect of that error Improvement � � Temperature was not considered and not counted as a controlled variable � � The concentration of milk was not

Fill each labeled cuvette with its corresponding volumetric flask label with a dropper 19) Fill the remaining unlabeled cuvette with water 20) Place the cuvette with water into the colorimeter and press green button to calibrate, do not do anything until the green light switches off by itself 21)

point where the glass rod was places to the point where the water was deflected. A protractor with a smallest increment of 0.5 degrees will be used to calculate the angle of deflection of the water. Controlling Variables Table 1 - Variables and Method of control Type Variable Method of

Covered shoes and Safety goggles were worn to avoid damage from spillage of HCl. 3. The work-table was wiped clean and dried before and after the experiment. RAW DATA COLLECTION: Volume of HCl required to neutralize each trial of each sample of substance Z solution was noted by reading the lower meniscus of the solution in the burette.

Human activity also impacts on waterways. Chemical monitoring and management assists in providing safe water for human use and to protect the habitats of other organisms. Point 5.1 ? Identify that water quality can be determined by considering: concentrations of common ions, total dissolved solids, hardness, turbidity, acidity, dissolved oxygen and biochemical oxygen demand (BOD).